How a Species Comes Back from the Brink of Extinction (Twice)!

As part of our efforts at Life Gone Wild to bring wildlife and conservation to everyone, we encourage people to request an animal. One that they think is cool, one they’d like to know more about, one that they think needs more attention. It could be almost any reason! Recently, we received our very first request. Little did we realise just how fascinating this species would end up being. This North American wonder has an amazing story. It includes extinction (twice), rediscovery, plagues, drones, genetic research, training schools, peanut butter, and the hard work of many, many people. We are delighted to be able to introduce you to one of the most endangered mammals in the world; the black-footed ferret!

Let’s get to know these hopeful poster-boys of North American conservation! The black-footed ferret is part of the largest family within the Carnivora order, the Mustelidae. This includes species like polecats, badgers, otters, wolverines, and more! Mustelids are distinguished by traits such as their short legs, thick fur, and their carnivorous tendencies. Most of the species within this family are nocturnal and live solitary lifestyles. The black-footed ferret is one of the most endangered animals on the North American continent, and is perhaps one of the most endangered mammals in the world! They have long, slender bodies that are for the most part a beige colour. Their fur turns black over their legs (hence the name), and they sport a black stripe down their spine. They have a white face with a black bandit mask over their eyes. They can grow up to 55cm in length (without the tail), making them slightly smaller than the domestic ferret. These gorgeous little critters inhabit the American prairies. They feed almost exclusively on prairie dogs and utilise burrows as shelter and to care for their kits (ferrets under one-year-old).

 A sleepy kit. Photo Credit: Kimberly Tamkun / USFWS

A sleepy kit. Photo Credit: Kimberly Tamkun / USFWS

This black-footed ferret was thought to be extinct twice, most recently around the late 1970s. However, in 1981 a small population was discovered in Wyoming. Sadly, the species nearly went extinct again, but these little mustelids are fighters. In an effort to save the species, a group of conservationists rounded up the last 18 individuals and formed a breeding centre! The first kits born at the centre were sent to the Smithsonian National Zoo and Conservation Biology Institute. Since that time, nearly 3,000 ferret kits have been released back into the wild under the U.S. Fish and Wildlife Service reintroduction program and over 7,000 being born since the program began. Today there are approximately 370 individual ferrets in the wild with another 280 in breeding facilities across the US. They’ve been reintroduced at 24 different sites, and four of them are considered to have self-sustaining populations as of 2015.

Huge efforts have been made to ensure the ongoing survival of the species. Over 30 federal, state, tribal and nongovernmental agencies are working together to conserve the species (U.S. Fish and Wildlife Service, 2015). However, the fight is not over yet. There are still some major issues threatening the black-footed ferret. In particular, diminished genetic diversity and recurrent disease outbreaks (impacting both the ferret and its prey) are causing headaches for those devoting time and resources to the survival of the black-footed ferret.

 A black-footed ferret leaping into the air as a part of a ferret war dance! Photo Credit: J. Michael Lockhart / USFWS

A black-footed ferret leaping into the air as a part of a ferret war dance! Photo Credit: J. Michael Lockhart / USFWS

The lack of genetic diversity within the ferret population is something that may well cause problems in the future. This particular threat is not entirely surprising, considering the small size of the initial population captured for conservation efforts. In fact, it is thought that all living ferrets today can be traced back to only seven founders, who do not even contribute to the population's genetic diversity equally. This is cause for concern because diminished genetic diversity leads to major issues within animal populations, including a lack of adaptability to wild conditions, decreased fertility, increased likelihood of genetic abnormalities, and an increased susceptibility to disease. This leads us nicely to the other big issue facing the black-footed ferret – disease.

The black-footed ferret is having massive issues with the sylvatic plague (Yersinia pestis). This bacterium is actually the same one that causes the bubonic plague in humans, and is transferred via flea bites, bodily fluids, and, well… by a ferret eating an infected prairie dog. This is a significant issue, as this disease has a huge impact upon both the prairie dogs (a mortality rate as high as 90%, and can wipe out entire colonies of prairie dogs in a number of weeks) and of course the black-footed ferrets. Unfortunately, the sylvatic plague has a 100% mortality rate when it comes to our rascals. While there is obviously a massive concern at how high that is for the ferrets, the bigger issue to their survival is actually the impact it has on the prairie dogs (National Wildlife Health Centre).

 A prairie dog, on high alert for a black-footed ferret! Photo Credit: Ryan Hagerty/ USFWS

A prairie dog, on high alert for a black-footed ferret! Photo Credit: Ryan Hagerty/ USFWS

The prairie dog is a keystone species of the North American prairies, and the black-footed ferret relies heavily upon them. Black-footed ferrets inhabit prairie dog burrows for shelter and to raise their young in. Most importantly though, the prairie dog makes up 90% of the ferret’s diet. It is thought that a single ferret could eat over 100 prairie dogs a year and that a family of ferrets would need over 250 prairie dogs over the same period to survive (Smithsonian’s National Zoo and Conservation Biology Institute). As a result, the loss of the prairie dog presents a pressing threat to the ongoing survival of the black-footed ferret. So much so, that the loss of prairie dogs during the 19th and 20th century (due to being seen as agricultural pests predominantly) has been attributed as the primary reason for the significant decline in the ferret population across North America. With this in mind, the conservation battle in the North American prairies becomes about not just the black-footed ferret, but also the prairie dog as well.

Conservationists and scientists though are working tirelessly to ensure ongoing survival for our ferret friends (and their prey!). For all of the parties involved creating long-term, self-sustaining populations of ferrets in the wild is the goal. However, the limited numbers in the wild that they have to work with currently, combined with the immediacy of the threats to their existence, is forcing both the conservationists and the scientists to get a bit creative in how they go about trying to keep the black-footed ferret alive. We’re going to quickly cover a few of the methods being tested and worked on that are providing so much hope for the survival of one of North America’s most endangered mammals.

 Black-footed Ferrets in Preconditioning Pens! Photo Credit: Ryan Moehring / USFWS

Black-footed Ferrets in Preconditioning Pens! Photo Credit: Ryan Moehring / USFWS

Genetic research presents a controversial yet promising path towards conservation of the black-footed ferret. Revive and Restore is the “leading organization promoting the incorporation of genetic tools into standard conservation practice,” according to their website. Through their work, they hope to be able to provide new insights into the genetics of endangered animals, as well as formulating potential rescue tools to face some of the most persistent challenges in conservation. Of course, accompanying any genetic work are a whole lot of questions, particularly of an ethical variety. We will delve into some of these prospective issues in a later post so for now back to Revive & Restore, and the work they are undertaking with the black-footed ferret!

The team at Revive & Restore is working hard in a few different areas. Firstly, they’re trying to map the genome of the black-footed ferret. Once this has been achieved they hope to compare their genome with that of the domestic ferret, who happens to have complete immunity to the sylvatic plague. If they can identify which gene the domestic ferret has that the black-footed ferret does not, then they might be able to attempt to transplant the gene into black-footed ferrets, providing them with this immunity! At this stage, the sylvatic plague vaccine provides lifetime immunity but requires capturing each individual ferret initially, before providing a booster 3 weeks after the initial dose (blackfootedferret.org). While all captive-born ferrets receive this, ensuring that wild-born ferrets get the vaccine is a labour-intensive undertaking, and does not seem realistic should populations achieve self-sustainability in the wild. Additionally, Revive & Restore are looking into the viability of IVF, which has never been conducted on ferrets before, as a means of introducing genetic variability to the black-footed ferret population. The genetic approach of Revive & Restore provides some real potential for long-term, self-sustaining populations that might just be able to overcome the threats of the sylvatic plague and the lack of genetic variability in black-footed ferret populations.

 Some inquisitive ferret kits poking their heads out from their burrows! Photo Credit: Kimberly Fraser / USFWS

Some inquisitive ferret kits poking their heads out from their burrows! Photo Credit: Kimberly Fraser / USFWS

Another really exciting technique being employed by a coalition of organisations the utilisation mechanised bait drops! This project is a joint effort between the United States Fish and Wildlife Service (USFWS), U.S. Geological Survey, World Wildlife Fund, the National Wildlife Health Centre, Model Avionics, and Support XXL. These organisations have come together and have come up with a remarkable conservation method. This coalition is airdropping peanut butter-flavoured (because duh), vaccine-laced baits from a number of different vehicles to try and save the prairie dogs, and as a result the black-footed ferret! While the project is still in testing stages, they currently are trialling these mechanized bait drops from three different vehicles (WWF). One system drops a single bait from an all-terrain vehicle (ATV), one drops three at a time from an ATV, and the third drops one bait from an unmanned aerial vehicle (UAV). So far, the results are promising! Field trials of the vaccine conducted in 2016 (across 2,000 acres of prairie dog colony, using the ATV methods) have shown that prairie dogs living within vaccinated areas are able to withstand ‘waves’ of the plague (National Public Radio). As of December 2017, those working with the UAV system were hoping to expose over 4,000 prairie dogs to the vaccine by the end of a working day.  

The third and final method that I’ll cover is also probably the one that I find the coolest! Now, remember earlier how the black-footed ferret became extinct in the wild (for the second time…) when they rounded up those final 18 ferrets? Most of the ferrets ever since have obviously been born in captivity as a result, and this can cause some issues. For biologists and conservationists working to save the species, one of the most important issues that this raises is ensuring that captive born ferrets still have the important behaviours and skills that they would need to survive in the wild. To ensure that this happens, the National Black-Footed Ferret Conservation Centre (NBFFCC) in Colorado has a rigorous preconditioning program that all reintroduced ferrets have gone through since 1996. Importantly, it has been shown that individuals that go to ferret school fare better in the wild when contrasted with ferrets that have not attended the preconditioning centre (Heim, 2011). But what does preconditioning mean when it comes to ferrets exactly?

 A ferret standing tall, looking out across the prairie! Photo Credit: Mike Lockhart / USFWS

A ferret standing tall, looking out across the prairie! Photo Credit: Mike Lockhart / USFWS

The preconditioning process that captive black-footed ferrets undergo prior to being released into the wild has been described as a “halfway house between captivity and reintroduction” (Heim, 2011). Here the ferrets get their first proper exposure to the elements in the 48 studio apartment-sized outdoor pens at the centre. The kits get placed into a pen with their littermates and/or their mother for a minimum of 30 days, getting released into the wild at around 120 days old, the time that they are naturally ready to separate from their family. During their time in the outdoor pens the kits learn how to live in and navigate through burrow systems (which make up their natural habitat on the prairies). They get used to living in natural conditions and all that that brings with it such as “cold and bugs, rain, snow, dust” (Heim, 2011). In addition to those conditions, in the past it has also meant training them to recognise and defend themselves against natural predators. This has included researchers swooping down on young ferrets with stuffed birds-of-prey, and sending in “robobadgers” (Heim 2011).

However, there is one factor at the end of the day that plays the biggest role in ensuring a successful transition from captivity into the wild. Ferrets that undergo the preconditioning training at the NBFFCC also get their first opportunity at hunting prairie dogs. It has been shown that the more practice and training a young kit gets hunting (and hopefully eating!) prairie dogs, the greater their chance of survival in the wild. To ensure that the preconditioning centre has enough prairie dogs to train the ferrets, they receive a number that are slated for extermination from across the western United States. While there are some groups that argue essentially for the rights of the prairie dogs, it is hard to argue with the strong evidence that shows the support of the program. A study by Biggins et al (1999) showed that working with live prey actually boosted ferret survival rate across the first nine months of living in the wild by tenfold (Biggins et al, 1999). These numbers are far too high to ignore I think, and illustrate just how successful the preconditioning program has been at preparing young, captive-born black-footed ferrets for living in the wilds of the North American grasslands.    

 A kit learning how to catch their prey, one of the most important skills a ferret can learn! Photo Credit: Kimberly Fraser / USFWS

A kit learning how to catch their prey, one of the most important skills a ferret can learn! Photo Credit: Kimberly Fraser / USFWS

To finish off with some recent, exciting (and perhaps even a tad serendipitous) news, wild-born black-footed ferrets have been found near Meeteetse, WY for the first time in 35 years! Meeteetse was the last, wild home of the black-footed ferret, so it has caused quite a bit of excitement within conservation circles in the area. The first kit found, in particular has a bit of a special connection to the town though. The mother of the kit is thought to be a ferret named Lucille, released by the Hogg family in 2016 and named for the late Lucille Hogg. It was Lucille that essentially rediscovered the species back in 1981 when her dog brought home a ferret it had caught in the night (Brown, 2017). For the first kits to be born (in the last, wild home of their ancestors) to a ferret named after the woman who confirmed that they were not extinct is, I think, just a little bit cool!

The black-footed ferret is a super interesting little critter. That they were thought to be extinct in the wild once, and then made to be extinct in the wild a second time, is practically unheard of! But it also makes the massive efforts of conservationists and scientists that much more remarkable! While the ongoing survival of this species is still not 100% certain, that they have been brought back from only 18 wild individuals is really exciting. The almost revolutionary methods being trialled by teams across the US provide great hope for the black-footed ferrets! Here at Life Gone Wild, we’re really glad that the case of the black-footed ferret was brought to our attention. Our research has filled us with hope that the situation of the black-footed ferret, having been in such a dire situation in the past, can surely only go up from here!

A massive shout out to Kate for requesting this fascinating little mammal! And perhaps an even bigger one to all of the amazing people working tirelessly to make sure that these incredible little guys live fight on!

 A group of NBFFCC employees going out to release black-footed ferrets! Credit: NPS

A group of NBFFCC employees going out to release black-footed ferrets! Credit: NPS

 

(For more information on the issues surrounding the genetic diversity of black-footed ferrets, and some of the ideas being bandied around that might help alleviate some of the pressure, check out this article https://academic.oup.com/jhered/article/106/5/581/2961879

If you want any other information either contact us or check out our list of references for this post just below!

 Just a little tongue action from a little cutie! Photo Credit: Ryan Moehring / USFWS

Just a little tongue action from a little cutie! Photo Credit: Ryan Moehring / USFWS

 

References

Biggins, D., Vargas, A., Godbey, J. and Anderson, S. (1999). Influence of prerelease experience on reintroduced black-footed ferrets (Mustela nigripes). Biological Conservation, [online] 89(2), pp.121-129. Available at: http://www.public.iastate.edu/~bsbowen/ZOOL-EEOB507/pdf/507wct_article.pdf.

Blackfootedferret.org. (2018). Disease | Black-Footed Ferret Recovery Program. [online] Available at: http://blackfootedferret.org/disease/ 

Blackfootedferret.org. (2018). Preconditioning | Black-Footed Ferret Recovery Program. [online] Available at: http://blackfootedferret.org/preconditioning/ 

Brown, A. (2018). Black-footed ferrets getting a boost in Wyoming. [online] Kgwn.tv. Available at: http://www.kgwn.tv/content/news/Black-footed-ferrets-getting-a-boost-in-Wyoming-442810123.html 

Cain, C., Livieri, T. and Swanson, B. (2011). Genetic evaluation of a reintroduced population of black-footed ferrets (Mustela nigripes). Journal of Mammalogy, [online] 92(4), pp.751-759. Available at: https://academic.oup.com/jmammal/article/92/4/751/887640.

Heim, M. (2011). Survival Training, Ferret Style. [online] Smithsonian. Available at: https://www.smithsonianmag.com/science-nature/survival-training-ferret-style-32562/ 

Holt, W. (2016). The black-footed ferret recovery program: a strong advocate for establishing semen banking programs as support tools for small population welfare. Animal Conservation, [online] 19(2), pp.116-117. Available at: http://onlinelibrary.wiley.com/doi/10.1111/acv.12270/epdf.

Howard, J., Lynch, C., Santymire, R., Marinari, P. and Wildt, D. (2015). Recovery of gene diversity using long-term cryopreserved spermatozoa and artificial insemination in the endangered black-footed ferret. Animal Conservation, [online] 19(2), pp.102-111. Available at: http://onlinelibrary.wiley.com/doi/10.1111/acv.12229/epdf.

Iucnredlist.org. (2018). Mustela nigripes (Black-footed Ferret). [online] Available at: http://www.iucnredlist.org/details/14020/0 

NPR.org. (2018). Biologists With Drones And Peanut Butter Pellets Are On A Mission To Help Ferrets. [online] Available at: https://www.npr.org/2017/12/10/569468428/biologists-with-drones-and-peanut-butter-pellets-are-on-a-mission-to-help-ferret 

Nwhc.usgs.gov. (2016). USGS National Wildlife Health Center - Sylvatic Plague. [online] Available at: https://www.nwhc.usgs.gov/disease_information/sylvatic_plague/ 

Region, U. (2018). Partnerships, Innovation (and Peanut Butter) Give New Hope for America’s Most Endangered Mammal. [online] Fws.gov. Available at: https://www.fws.gov/mountain-prairie/pressrel/2016/10182016-Partnerships-Innovation-and-Peanut-Butter-Give-New-Hope-for-Americas-Most-Endangered-Mammal.php

Revive & Restore. (2018). Black-Footed Ferret. [online] Available at: http://reviverestore.org/projects/black-footed-ferret/ 

Smithsonian's National Zoo & Conservation Biology Institute. (2018). Black-footed ferret. [online] Available at: https://nationalzoo.si.edu/animals/black-footed-ferret 

Wisely, S., Ryder, O., Santymire, R., Engelhardt, J. and Novak, B. (2015). A Road Map for 21st Century Genetic Restoration: Gene Pool Enrichment of the Black-Footed Ferret. Journal of Heredity, [online] 106(5), pp.581-592. Available at: https://academic.oup.com/jhered/article/106/5/581/2961879.

World Wildlife Fund. (2016). Innovations (and peanut butter) give black-footed ferrets a boost. [online] Available at: https://www.worldwildlife.org/stories/innovations-and-peanut-butter-give-black-footed-ferrets-a-boost